Search Results: "cts"

29 July 2020

Enrico Zini: Building and packaging a sysroot

This is part of a series of posts on compiling a custom version of Qt5 in order to develop for both amd64 and a Raspberry Pi. After having had some success with a sysroot in having a Qt5 cross-build environment that includes QtWebEngine, the next step is packaging the sysroot so it can be available both to build the cross-build environment, and to do cross-development with it. The result is this Debian source package which takes a Raspberry Pi OS disk image, provisions it in-place, extracts its contents, and packages them. Yes. You may want to reread the last paragraph. It works directly in the disk image to avoid a nasty filesystem issue on emulated 32bit Linux over a 64bit mounted filesystem. This feels like the most surreal Debian package I've ever created, and this saga looks like one of the hairiest yaks I've ever shaved. Integrating this monster codebase, full of bundled code and hacks, into a streamlined production and deployment system has been for me a full stack nightmare, and I have a renewed and growing respect for the people in the Qt/KDE team in Debian, who manage to stay on top of this mess, so that it all just works when we need it.

28 July 2020

Chris Lamb: Pop culture matters

Many people labour under the assumption that pop culture is trivial and useless while only 'high' art can grant us genuine and eternal knowledge about the world. Given that we have a finite time on this planet, we are all permitted to enjoy pop culture up to a certain point, but we should always minimise our interaction with it, and consume more moral and intellectual instruction wherever possible. Or so the theory goes. What these people do not realise is that pop and mass culture can often provide more information about the world, humanity in general and what is even more important ourselves. This is not quite the debate around whether high art is artistically better, simply that pop culture can be equally informative. Jeremy Bentham argued in the 1820s that "prejudice apart, the game of push-pin is of equal value with the arts and sciences of music and poetry", that it didn't matter where our pleasures come from. (John Stuart Mill, Bentham's intellectual rival, disagreed.) This fundamental question of philosophical utilitarianism will not be resolved here. However, what might begin to be resolved is our instinctive push-back against pop culture. We all share an automatic impulse to disregard things we do not like and to pretend they do not exist, but this wishful thinking does not mean that these cultural products do not continue to exist when we aren't thinking about them and, more to our point, continue to influence others and even ourselves. Take, for example, the recent trend for 'millennial pink'. With its empty consumerism, faux nostalgia, reductive generational stereotyping, objectively ugly sthetics and tedious misogyny (photographed with Rose Gold iPhones), the very combination appears to have been deliberately designed to annoy me, curiously providing circumstantial evidence in favour of intelligent design. But if I were to immediately dismiss millennial pink and any of the other countless cultural trends I dislike simply because I find them disagreeable, I would be willingly keeping myself blind to their underlying ideology, their significance and their effect on society at large. If I had any ethical or political reservations I might choose not to engage with them economically or to avoid advertising them to others, but that is a different question altogether. Even if we can't notice this pattern within ourselves we can first observe it in others. We can all recall moments where someone has brushed off a casual reference to pop culture, be it Tiger King, TikTok, team sports or Taylor Swift; if you can't, simply look for the abrupt change of tone and the slightly-too-quick dismissal. I am not suggesting you attempt to dissuade others or even to point out this mental tic, but merely seeing it in action can be highly illustrative in its own way. In summary, we can simultaneously say that pop culture is not worthy of our time relative to other pursuits while consuming however much of it we want, but deliberately dismissing pop culture doesn't mean that a lot of other people are not interacting with it and is therefore undeserving of any inquiry. And if that doesn't convince you, just like the once-unavoidable millennial pink, simply sticking our collective heads in the sand will not mean that wider societal-level ugliness is going to disappear anytime soon. Anyway, that's a very long way of justifying why I plan to re-watch TNG.

Dirk Eddelbuettel: ttdo 0.0.6: Bugfix

A bugfix release of our (still small) ttdo package arrived on CRAN overnight. As introduced last fall, the ttdo package extends the most excellent (and very minimal / zero depends) unit testing package tinytest by Mark van der Loo with the very clever and well-done diffobj package by Brodie Gaslam to give us test results with visual diffs: ttdo screenshot This release corrects a minor editing error spotted by the ever-vigilant John Blischak. The NEWS entry follow.

Changes in ttdo version 0.0.6 (2020-07-27)
  • Correct a minor editing mistake spotted by John Blischak.

CRANberries provides the usual summary of changes to the previous version. Please use the GitHub repo and its issues for any questions. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Steve Kemp: I'm a bit of a git (hacker?)

Sometimes I enjoy reading the source code to projects I like, use, or am about to install for the first time. This was something I used to do on a very regular basis, looking for security issues to report. Nowadays I don't have so much free time, but I still like to inspect the source code to new applications I install, and every now and again I'll find the time to look at the source to random projects. Reading code is good. Reading code is educational. One application I've looked at multiple times is redis, which is a great example of clean and well-written code. That said when reading the redis codebase I couldn't help noticing that there were a reasonably large number of typos/spelling mistakes in the comments, so I submitted a pull-request: Sadly that particular pull-request didn't receive too much attention, although a previous one updating the configuration file was accepted. I was recently reminded of these pull-requests when I was when I was doing some other work. So I figured I'd have a quick scan of a couple of other utilities. In the past I'd just note spelling mistakes when I came across them, usually I'd be opening each file in a project one by one and reading them from top to bottom. (Sometimes I'd just open files in emacs and run "M-x ispell-comments-and-strings", but more often I'd just notice them with my eyes). It did strike me that if I were to do this in a more serious fashion it would be good to automate it. So this time round I hacked up a simple "dump comments" utility, which would scan named files and output the contents of any comments (be they single-line, or multi-line). Once I'd done that I could spell-check easily: 
 $ go run dump-comments.go *.c > comments
 $ aspell -c comments
Anyway the upshot of that was a pull-request against git: We'll see if that makes its way live sometime. In case I get interested in doing this again I've updated my sysbox-utility collection to have a comments sub-command. That's a little more robust and reliable than my previous hack: 
$ sysbox comments -pretty=true $(find . -name '*.c')
..
..
The comments sub-command has support for: Adding new support would be trivial, I just need a start and end pattern to search against. Pull-requests welcome:

27 July 2020

Matthew Garrett: Filesystem deduplication is a sidechannel

First off - nothing I'm going to talk about in this post is novel or overly surprising, I just haven't found a clear writeup of it before. I'm not criticising any design decisions or claiming this is an important issue, just raising something that people might otherwise be unaware of.

With that out of the way: Automatic deduplication of data is a feature of modern filesystems like zfs and btrfs. It takes two forms - inline, where the filesystem detects that data being written to disk is identical to data that already exists on disk and simply references the existing copy rather than, and offline, where tooling retroactively identifies duplicated data and removes the duplicate copies (zfs supports inline deduplication, btrfs only currently supports offline). In a world where disks end up with multiple copies of cloud or container images, deduplication can free up significant amounts of disk space.

What's the security implication? The problem is that deduplication doesn't recognise ownership - if two users have copies of the same file, only one copy of the file will be stored[1]. So, if user a stores a file, the amount of free space will decrease. If user b stores another copy of the same file, the amount of free space will remain the same. If user b is able to check how much free space is available, user b can determine whether the file already exists.

This doesn't seem like a huge deal in most cases, but it is a violation of expected behaviour (if user b doesn't have permission to read user a's files, user b shouldn't be able to determine whether user a has a specific file). But we can come up with some convoluted cases where it becomes more relevant, such as law enforcement gaining unprivileged access to a system and then being able to demonstrate that a specific file already exists on that system. Perhaps more interestingly, it's been demonstrated that free space isn't the only sidechannel exposed by deduplication - deduplication has an impact on access timing, and can be used to infer the existence of data across virtual machine boundaries.

As I said, this is almost certainly not something that matters in most real world scenarios. But with so much discussion of CPU sidechannels over the past couple of years, it's interesting to think about what other features also end up leaking information in ways that may not be obvious.

(Edit to add: deduplication isn't enabled on zfs by default and is explicitly triggered on btrfs, so unless it's something you've enabled then this isn't something that affects you)

[1] Deduplication is usually done at the block level rather than the file level, but given zfs's support for variable sized blocks, identical files should be deduplicated even if they're smaller than the maximum record size

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Russ Allbery: Review: Rise of the Warrior Cop

Review: Rise of the Warrior Cop, by Radley Balko
Publisher: PublicAffairs
Copyright: 2013
ISBN: 1-61039-212-4
Format: Kindle
Pages: 336
As the United States tries, in fits and starts, to have a meaningful discussion about long-standing police racism, brutality, overreach, corruption, and murder, I've realized that my theoretical understanding of the history of and alternative frameworks for law enforcement is woefully lacking. Starting with a book by a conservative white guy is not the most ideal of approaches, but it's what I already had on hand, and it won't be the last book I read and review on this topic. (Most of my research so far has been in podcast form. I don't review those here, but I can recommend Ezra Klein's interviews with Ta-Nehisi Coates, Paul Butler, and, most strongly, sujatha baliga.) Rise of the Warrior Cop is from 2013 and has had several moments of fame, no doubt helped by Balko's connections to the conservative and libertarian right. One of the frustrating facts of US politics is that critiques of the justice system from the right (and from white men) get more media attention than critiques from the left. That said, it's a generally well-respected book on the factual history of the topic, and police brutality and civil rights are among the points on which I have stopped-clock agreements with US libertarians. This book is very, very libertarian. In my callow youth, I was an ardent libertarian, so I've read a lot of US libertarian literature. It's a genre with its own conventions that become obvious when you read enough of it, and Rise of the Warrior Cop goes through them like a checklist. Use the Roman Republic (never the Roman Empire) as the starting point for any political discussion, check. Analyze the topic in the context of pre-revolutionary America, check. Spend considerable effort on discerning the opinions of the US founders on the topic since their opinions are always relevant to the modern world, check. Locate some point in the past (preferably before 1960) where the political issue was as good as it has ever been, check. Frame all changes since then as an erosion of rights through government overreach, check. Present your solution as a return to a previous era of respect for civil rights, check. Once you start recognizing the genre conventions, their prevalence in libertarian writing is almost comical. The framing chapters therefore leave a bit to be desired, but the meat of the book is a useful resource. Starting with the 1970s and its use as a campaigning tool by Nixon, Balko traces a useful history of the war on drugs. And starting with the 1980s, the number of cites to primary sources and the evidence of Balko's own research increases considerably. If you want to know how US police turned into military cosplayers with body armor, heavy weapons, and armored vehicles, this book provides a lot of context and history. One of the reasons why I view libertarians as allies of convenience on this specific issue is that drug legalization and disgust with the war on drugs have been libertarian issues for decades. Ideologically honest libertarians (and Balko appears to be one) are inherently skeptical of the police, so when the police overreach in an area of libertarian interest, they notice. Balko makes a solid argument, backed up with statistics, specific programs, legislation, and court cases, that the drug war and its accompanying lies about heavily-armed drug dealers and their supposed threat to police officers was the fuel for the growth of SWAT teams, no-knock search warrants, erosion of legal protections for criminal defendants, and de facto license for the police to ignore the scope and sometimes even the existence of warrants. This book is useful support for the argument that fears for the safety of officers underlying the militarization of police forces are imaginary. One telling point that Balko makes repeatedly and backs with statistical and anecdotal evidence is that the police generally do not use raid tactics on dangerous criminals. On the contrary, aggressive raids are more likely to be used on the least dangerous criminals because they're faster, they're fun for the police (they provide an adrenaline high and let them play with toys), and they're essentially risk-free. If the police believe someone is truly dangerous, they're more likely to use careful surveillance and to conduct a quiet arrest at an unexpected moment. The middle-of-the-night armed break-ins with battering rams, tear gas, and flash-bangs are, tellingly, used against the less dangerous suspects. This is part of Balko's overall argument that police equipment and tactics have become untethered from any realistic threat and have become cultural. He traces an acceleration of that trend to 9/11 and the resulting obsession with terrorism, which further opened the spigot of military hardware and "special forces" training. This became a point of competition between police departments, with small town forces that had never seen a terrorist and had almost no chance of a terrorist incident demanding their own armored vehicles. I've encountered this bizarre terrorism justification personally; one of the reasons my local police department gave in a public hearing for not having a policy against shooting at moving vehicles was "but what if terrorism?" I don't believe there has ever been a local terrorist attack. SWAT in such places didn't involve the special training or dedicated personnel of large city forces; instead, it was a part-time duty for normal police officers, and frequently they were encouraged to practice SWAT tactics by using them at random for some otherwise normal arrest or search. Balko argues that those raids were more exciting than normal police work, leading to a flood of volunteers for that duty and a tendency to use them as much as possible. That in turn normalizes disconnecting police tactics from the underlying crime or situational risk. So far, so good. But despite the information I was able to extract from it, I have mixed feelings about Rise of the Warrior Cop as a whole. At the least, it has substantial limitations. First, I don't trust the historical survey of policing in this book. Libertarian writing makes for bad history. The constraints of the genre require overusing only a few points of reference, treating every opinion of the US founders as holy writ, and tying forward progress to a return to a previous era, all of which interfere with good analysis. Balko also didn't do the research for the historical survey, as is clear from the footnotes. The citations are all to other people's histories, not to primary sources. He's summarizing other people's histories, and you'll almost certainly get better history by finding well-respected historians who cover the same ground. (That said, if you're not familiar with Peel's policing principles, this is a good introduction.) Second, and this too is unfortunately predictable in a libertarian treatment, race rarely appears in this book. If Balko published the same book today, I'm sure he would say more about race, but even in 2013 its absence is strange. I was struck while reading by how many examples of excessive police force were raids on west coast pot farms; yes, I'm sure that was traumatic, but it's not the demographic I would name as the most vulnerable to or affected by police brutality. West coast pot growers are, however, mostly white. I have no idea why Balko made that choice. Perhaps he thought his target audience would be more persuaded by his argument if he focused on white victims. Perhaps he thought it was an easier and less complicated story to tell. Perhaps, like a lot of libertarians, he doesn't believe racism has a significant impact on society because it would be a market failure. Perhaps those were the people who more readily came to mind. But to talk about police militarization, denial of civil rights, and police brutality in the United States without putting race at the center of both the history and the societal effects leaves a gaping hole in the analysis. Given that lack of engagement, I also am dubious of Balko's policy prescriptions. His reform suggestions aren't unreasonable, but they stay firmly in the centrist and incrementalist camp and would benefit white people more than black people. Transparency, accountability, and cultural changes are all fine and good, but the cultural change Balko is focused on is less aggressive arrest tactics, more use of mediation, and better physical fitness. I would not object to those things (well, maybe the last, which seemed odd), but we need to have a discussion about police white supremacist organizations, the prevalence of spousal abuse, and the police tendency to see themselves not as public servants but as embattled warriors who are misunderstood by the naive sheep they are defending. And, of course, you won't find in Rise of the Warrior Cop any thoughtful wrestling with whether there are alternative approaches to community safety, whether punitive rather than restorative justice is effective, or whether crime is a symptom of deeper societal problems we could address but refuse to. The most radical suggestion Balko has is to legalize drugs, which is both the predictable libertarian position and, as we have seen from recent events in the United States, far from the only problem of overcriminalization. I understand why this book is so frequently mentioned on-line, and its author's political views may make it more palatable to some people than a more race-centered or radical perspective. But I don't think this is the best or most useful book on police violence that one could read today. I hope to find a better one in upcoming reviews. Rating: 6 out of 10

25 July 2020

Niels Thykier: Support for Debian packaging files in IDEA (IntelliJ/PyCharm)

I have been using the community editions of IntelliJ and PyCharm for a while now for Python or Perl projects. But it started to annoy me that for Debian packaging bits it would revert into a fancy version of notepad. Being fed up with it, I set down and spent the last week studying how to write a plugin to fix this.

After a few prototypes, I have now released IDEA-debpkg v0.0.3 (Link to JetBrain s official plugin listing with screenshots). It provides a set of basic features for debian/control like syntax highlighting, various degree of content validation, folding of long fields, code completion and CTRL + hover documentation. For debian/changelog, it is mostly just syntax highlighting with a bit of fancy linking for now. I have not done anything for debian/rules as I noted there is a Makefile plugin, which will have to do for now.

The code is available from github and licensed under Apache-2.0. Contributors, issues/feature requests and pull requests are very welcome. Among things I could help with are:

I hope you will take it for spin if you have been looking for a bit of Debian packaging support to your PyCharm or other IDEA IDE. Please do file bugs/issues if you run into issues, rough edges or unhelpful documentation, etc.

24 July 2020

Dirk Eddelbuettel: anytime 0.3.8: Minor Maintenance

A new minor release of the anytime package arrived on CRAN overnight. This is the nineteenth release, and it comes just over six months after the previous release giving further indicating that we appear to have reached a nice level of stability. anytime is a very focused package aiming to do just one thing really well: to convert anything in integer, numeric, character, factor, ordered, format to either POSIXct or Date objects and to do so without requiring a format string. See the anytime page, or the GitHub README.md for a few examples. This release mostly plays games with CRAN. Given the lack of specification for setups on their end, reproducing test failures remains, to put it mildly, somewhat challenging . So we eventually gave up and weaponed up once more and now explicitly test for the one distribution where tests failed (when they clearly passed everywhere else). With that we now have three new logical predicates for various Linux distribution flavours, and if that dreaded one is seen in one test file the test is skipped. And with that we now score twelve out of twelve OKs. This being a game of cat and mouse, I am sure someone somewhere will soon invent a new test The full list of changes follows.

Changes in anytime version 0.3.8 (2020-07-23)
  • A small utility function was added to detect the Linux distribution used in order to fine-tune tests once more.
  • Travis now uses Ubuntu 'bionic' and R 4.0.*.

Courtesy of CRANberries, there is a comparison to the previous release. More information is on the anytime page. The issue tracker tracker off the GitHub repo can be use for questions and comments. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Mike Gabriel: Ayatana Indicators / IDO - Menu Rendering Fixed with vanilla GTK-3+

At DebConf 17 in Montreal, I gave a talk about Ayatana Indicators [1] and the project's goal to continue the by then already dropped out of maintenance Ubuntu Indicators in a separate upstream project, detached from Ubuntu and its Ubuntu'isms. Stalling The whole Ayatana Indicators project received a bit of a show stopper by the fact that the IDO (Indicator Display Object) rendering was not working in vanilla GTK-3 without a certain patch [2] that only Ubuntu has in their GTK-3 package. Addressing GTK developers upstream some years back (after GTK 3.22 had already gone into long term maintenance mode) and asking for a late patch acceptance did not work out (as already assumed). Ayatana Indicators stalled at a level of 90% actually working fine, but those nice and shiny special widgets, like the calendar widget, the audio volume slider widgets, switch widgets, etc. could not be rendered appropriately in GTK based desktop environments (e.g. via MATE Indicator Applet) on other distros than Ubuntu. I never really had the guts to sit down without a defined ending and find a patch / solution to this nasty problem. Ayatana Indicators stalled as a whole. I kept it alive and defended its code base against various GLib and what-not deprecations and kept it in Debian, but the software was actually partially broken / dysfunctional. Taking the Dog for a Walk and then It Became all Light+Love Several days back, I received a mail from Robert Tari [3]. I was outside on a hike with our dog and thought, ah well, let's check emails... I couldn't believe what I read then, 15 seconds later. I could in fact, hardly breathe... I have known Robert from earlier email exchanges. Robert maintains various "little" upstream projects, like e.g. Caja Rename, Odio, Unity Mail, etc. that I have looked into earlier regarding Debian packaging. Robert is also a Manjaro contributor and he has been working on bringing Ayatana Indicators to Manjaro MATE. In the early days, without knowing Robert, I even forked one of his projects (indicator-notification) and turned it into an Ayatana Indicator. Robert and I also exchanged some emails about Ayatana Indicators already a couple of weeks ago. I got the sense of him maybe being up to something already then. Oh, yeah!!! It turned out that Robert and I share the same "love" for the Ubuntu Indicators concept [4]. From his email, it became clear that Robert had spent the last 1-2 weeks drowned in the Ayatana IDO and libayatana-indicator code and worked him self through the bowels of it in order to understand the code concept of Indicators to its very depth. When emerging back from his journey, he presented me (or rather: the world) a patch [5] against libayatana-indicator that makes it possible to render IDO objects even if a vanilla GTK-3 is installed on the system. This patch is a game changer for Indicator lovers. When Robert sent me his mail pointing me to this patch, I think, over the past five years, I have never felt more excited (except from the exact moment of getting married to my wife two-to-three years ago) than during that moment when my brain tried to process his email. "Like a kid on Christmas Eve...", Robert wrote in one of his later mails to me. Indeed, like a "kid on Christmas Eve", Robert. Try It Out As a proof of all this to the Debian people, I have just done the first release of ayatana-indicator-datetime and uploaded it to Debian's NEW queue. Robert is doing the same for Manjaro. The Ayatana Indicator Sound will follow after my vacation. For fancy widget rendering in Ayatana Indicator's system indicators, make sure you have libayatana-indicator 0.7.0 or newer installed on your system. Credits One of the biggest thanks ever I send herewith to Robert Tari! Robert is now co-maintainer of Ayatana Indicators. Welcome! Now, there is finally a team of active contributors. This is so delightful!!! References P.S. Expect more Ayatana Indicators to appear in your favourite distro soon...

Martin Michlmayr: beancount2ledger 1.1 released

Martin Blais recently announced that he'd like to re-organize the beancount code and split out some functionality into separate projects, including the beancount to ledger/hledger conversion code previously provided by bean-report. I agreed to take on the maintenance of this code and I've now released beancount2ledger, a beancount to ledger/hledger converter. You can install beancount2ledger with pip: 
pip3 install beancount2ledger
Please report issues to the GitHub tracker. There are a number of outstanding issues I'll fix soon, but please report any other issues you encounter. Note that I'm not very familiar with hledger. I intend to sync up with hledger author Simon Michael soon, but please file an issue if you notice any problems with the hledger conversion. Version 1.1 contains a number of fixes compared to the latest code in bean-report: 1.1 (2020-07-24) 1.0 (2020-07-22)

23 July 2020

Sean Whitton: keyboardingupdates

Marks and mark rings in GNU Emacs I recently attempted to answer the question of whether experienced Emacs users should consider partially or fully disabling Transient Mark mode, which is (and should be) the default in modern GNU Emacs. That blog post was meant to be as information-dense as I could make it, but now I d like to describe the experience I have been having after switching to my custom pseudo-Transient Mark mode, which is labelled mitigation #2 in my older post. In summary: I feel like I ve uncovered a whole editing paradigm lying just beneath the surface of the editor I ve already been using for years. That is cool and enjoyable in itself, but I think it s also helped me understand other design decisions about the basics of the Emacs UI better than before in particular, the ideas behind how Emacs chooses where to display buffers, which were very frustrating to me in the past. I am now regularly using relatively obscure commands like C-x 4 C-o. I see it! It all makes sense now! I would encourage everyone who has never used Emacs without Transient Mark mode to try turning it off for a while, either fully or partially, just to see what you can learn. It s fascinating how it can come to seem more convenient and natural to pop the mark just to go back to the end of the current line after fixing up something earlier in the line, even though doing so requires pressing two modified keys instead of just C-e. Eshell I was amused to learn some years ago that someone was trying to make Emacs work as an X11 window manager. I was amazed and impressed to learn, more recently, that the project is still going and a fair number of people are using it. Kudos! I suspect that the basic motivation for such projects is that Emacs is a virtual Lisp machine, and it has a certain way of managing visible windows, and people would like to be able to bring both of those to their X11 window management. However, I am beginning to suspect that the intrinsic properties of Emacs buffers are tightly connected to the ways in which Emacs manages visible windows, and the intrinsic properties of Emacs buffers are at least as fundamental as its status as a virtual Lisp machine. Thus I am not convinced by the idea of trying to use Emacs ways of handling visible windows to handle windows which do not contain Emacs buffers. (but it s certainly nice to learn it s working out for others) The more general point is this. Emacs buffers are as fundamental to Emacs as anything else is, so it seems unlikely to be particularly fruitful to move something typically done outside of Emacs into Emacs, unless that activity fits naturally into an Emacs buffer or buffers. Being suited to run on a virtual Lisp machine is not enough. What could be more suited to an Emacs buffer, however, than a typical Unix command shell session? By this I mean things like running commands which produce text output, and piping this output between commands and into and out of files. Typically the commands one enters are sort of like tiny programs in themselves, even if there are no pipes involved, because you have to spend time determining just what options to pass to achieve what you want. It is great to have all your input and output available as ordinary buffer text, navigable just like all your other Emacs buffers. Full screen text user interfaces, like top(1), are not the sort of thing I have in mind here. These are suited to terminal emulators, and an Emacs buffer makes a poor terminal emulator what you end up with is a sort of terminal emulator emulator. Emacs buffers and terminal emulators are just different things. These sorts of thoughts lead one to Eshell, the Emacs Shell. Quoting from its documentation:
The shell s role is to make [system] functionality accessible to the user in an unformed state. Very roughly, it associates kernel functionality with textual commands, allowing the user to interact with the operating system via linguistic constructs. Process invocation is perhaps the most significant form this takes, using the kernel s fork' andexec functions. Emacs is a user application, but it does make the functionality of the kernel accessible through an interpreted language namely, Lisp. For that reason, there is little preventing Emacs from serving the same role as a modern shell. It too can manipulate the kernel in an unpredetermined way to cause system changes. All it s missing is the shell-ish linguistic model.
Eshell has been working very well for me for the past month or so, for, at least, Debian packaging work, which is very command shell-oriented (think tools like dch(1)). The other respects in which Eshell is tightly integrated with the rest of Emacs are icing on the cake. In particular, Eshell can transparently operate on remote hosts, using TRAMP. So when I need to execute commands on Debian s ftp-master server to process package removal requests, I just cd /ssh:fasolo: in Eshell. Emacs takes care of disconnecting and connecting to the server when needed there is no need to maintain a fragile SSH connection and a shell process (or anything else) running on the remote end. Or I can cd /ssh:athena\ sudo:root@athena: to run commands as root on the webserver hosting this blog, and, again, the text of the session survives on my laptop, and may be continued at my leisure, no matter whether athena reboots, or I shut my laptop and open it up again the next morning. And of course you can easily edit files on the remote host.

21 July 2020

Enrico Zini: Screen ghosts

I noticed an odd effect, that reminds me of screen ghosting on old CRT monitors, when my laptop screen is locked: Those faint white vertical lines one can see, are actually window borders, and the lock screen is leaking contents of my unlocked desktop! Here is the same screen, unlocked: However, moving the windows around does not reflect on the ghost image on top of the lock screen: reshuffling windows then locking, produces always the same ghost image. The white border reflects where the window has been at some time in the past. The lock screen does not seem to be responsible, either: dragging a solid colored window on the laptop screen has the same effect: But taking a screenshot of it does not show the time traveling ghost windows: This is happening on two different laptops, an HP EliteBook x360 G1, and a Lenovo ThinkPad X240, one that I've been using since 3 years, one that I've been using since a week, and whose only thing in common is a 1920x1080 IPS screen and an Intel GPU. I have no idea where to start debugging this. Please reach out to me at enrico@debian.org if any of this makes sense to you. Update: Jim Paris pointed me to https://en.wikipedia.org/wiki/Image_persistence which looks pretty much like what is happening here. Jim Paris also pointed out that a black background doesn't show the ghosting. I changed the lock screen background by editing /etc/lightdm/lightdm-gtk-greeter.conf and adding background=#000000 to the [greeter] section, to limit information leakage through ghosting in the lock screen.

20 July 2020

Dominique Dumont: Security gotcha with log collection on Azure Kubernetes cluster.

Azure Kubernetes Service provides a nice way to set up Kubernetes
cluster in the cloud. It s quite practical as AKS is setup by default
with a rich monitoring and reporting environment. By default, all
container logs are collected, CPU and disk data are gathered. I used AKS to setup a cluster for my first client as a
freelance. Everything was nice until my client asked me why logs
collection was as expensive as the computer resources. Ouch My first reflex was to reduce the amount of logs produced by all our
containers, i.e. start logging at warn level instead of info
level. This reduced the amount of logs quite a lot. But this did not reduce the cost of collecting logs, which looks like
to a be a common issue. Thanks to the documentation provided by Microsoft, I was able to find
that ContainerInventory data table was responsible of more than 60%
of our logging costs. What is ContainerInventory ? It s a facility to monitor the content
of all environment variables from all containers. Wait What ? Should we be worried about our database credentials which are, legacy
oblige, stored in environment variables ? Unfortunately, the query shown below confirmed that, yes, we should:
the logs aggregated by Azure contains the database credentials of my
client. 
ContainerInventory
  where TimeGenerated > ago(1h)
Having credentials collected in logs is lackluster from a security
point of view. And we don t need it because our environment variables do not change. Well, it s now time to fix these issues. We re going to:
  1. disable the collection of environment variables in Azure, which
    will reduce cost and plug the potential credential leak
  2. renew all DB credentials, because the previous credentials can be
    considered as compromised (The renewal of our DB passwords is quite
    easy with the script I provided to my client)
  3. pass credentials with files instead of environment variables.
In summary, the service provided by Azure is still nice, but beware of
the default configuration which may contain surprises. I m a freelance, available for hire. The https://code-straight.fr site
describes how I can help your projects. All the best

18 July 2020

Dirk Eddelbuettel: tint 0.1.3: Fixes for html mode, new demo

A new version 0.1.3 of the tint package arrived at CRAN today. It corrects some features for html output, notably margin notes and references. It also contains a new example for inline references. The full list of changes is below.

Changes in tint version 0.1.3 (2020-07-18)
  • A new minimal demo was added showing inline references (Dirk addressing #42).
  • Code for margin notes and reference in html mode was updated with thanks to tufte (Dirk in #43 and #44 addressing #40).
  • The README.md was updated with a new 'See Also' section and a new badge.

Courtesy of CRANberries, there is a comparison to the previous release. More information is on the tint page. For questions or comments use the issue tracker off the GitHub repo.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Abhijith PA: Workstation setup

Workstation Hello, Recently I ve seen lot of people sharing about their home office setup. I thought why don t I do something similar. Not to beat FOMO, but in future when I revisit this blog, it will be lovely to understand that I had some cool stuffs. There are people who went deep down in the ocean to lay cables for me to have a remote job and I am thankful to them. Being remote my home is my office. On my work table I have a Samsung R439 laptop. I ve blogged about it earlier. New addition is that it have another 4GB RAM, a total of 6GB and 120GB SSD. I run Debian testing on it. Laptop is placed on a stand. Dell MS116 as external mouse always connected to it. I also use an external keyboard from fingers. The keys are very stiff so I don t recommend this to anyone. The only reason I took this keyboard that it is in my budget and have a backlit, which I needed most. I have a Micromax MM215FH76 21 inch monitor as my secondary display which stacked up on couple of old books to adjust the height with laptop stand. Everything is ok with this monitor except that it don t have a HDMI point and stand is very weak. I use i3wm and this small script help me to manage my monitor arrangement. 
# samsung r439
xrandr --output LVDS1 --primary --mode 1366x768 --pos 1920x312 --rotate normal --output DP1 --off --output HDMI1 --off --output VGA1 --mode 1920x1080 --pos 0x0 --rotate normal --output VIRTUAL1 --off
# thinkpad t430s
#xrandr --output LVDS1 --primary --mode 1600x900 --pos 1920x180 --rotate normal --output DP1 --off --output DP2 --off --output DP3 --off --output HDMI1 --off --output HDMI2 --off --output HDMI3 --off --output VGA1 --mode 1920x1080 --pos 0x0 --rotate normal --output VIRTUAL1 --off
i3-msg workspace 2, move workspace to left
i3-msg workspace 4, move workspace to left
i3-msg workspace 6, move workspace to left
I also have another Viewsonic monitor 19 inch, it started to show some lines and unpleasant colors. Thus moved back to shelf. I have an orange pi zero plus 2 running Armbian which serve as my emby media server. I don t own any webcam or quality headset at the moment. I have a boat, and Mi, headphones. My laptop inbuilt webcam is horrible, so for my video conferencing need I use jitsi app on my mobile device.

Abhijith PA: Workstation setup

Workstation Hello, Recently I ve seen lot of people sharing about their home office setup. I thought why don t I do something similar. Not to beat FOMO, but in future when I revisit this blog, it will be lovely to understand that I had some cool stuffs. There are people who went deep down in the ocean to lay cables for me to have a remote job and I am thankful to them. Being remote my home is my office. On my work table I have a Samsung R439 laptop. I ve blogged about it earlier. New addition is that it have another 4GB RAM, a total of 6GB and 120GB SSD. I run Debian testing on it. Laptop is placed on a stand. Dell MS116 as external mouse always connected to it. I also use an external keyboard from fingers. The keys are very stiff so I don t recommend this to anyone. The only reason I took this keyboard that it is in my budget and have a backlit, which I needed most. I have a Micromax MM215FH76 21 inch monitor as my secondary display which stacked up on couple of old books to adjust the height with laptop stand. Everything is ok with this monitor except that it don t have a HDMI point and stand is very weak. I use i3wm and this small script help me to manage my monitor arrangement. 
# samsung r439
xrandr --output LVDS1 --primary --mode 1366x768 --pos 1920x312 --rotate normal --output DP1 --off --output HDMI1 --off --output VGA1 --mode 1920x1080 --pos 0x0 --rotate normal --output VIRTUAL1 --off
# thinkpad t430s
#xrandr --output LVDS1 --primary --mode 1600x900 --pos 1920x180 --rotate normal --output DP1 --off --output DP2 --off --output DP3 --off --output HDMI1 --off --output HDMI2 --off --output HDMI3 --off --output VGA1 --mode 1920x1080 --pos 0x0 --rotate normal --output VIRTUAL1 --off
i3-msg workspace 2, move workspace to left
i3-msg workspace 4, move workspace to left
i3-msg workspace 6, move workspace to left
I also have another Viewsonic monitor 19 inch, it started to show some lines and unpleasant colors. Thus moved back to shelf. I have an orange pi zero plus 2 running Armbian which serve as my emby media server. I don t own any webcam or quality headset at the moment. I have a boat, and Mi, headphones. My laptop inbuilt webcam is horrible, so for my video conferencing need I use jitsi app on my mobile device.

17 July 2020

Dirk Eddelbuettel: RcppArmadillo 0.9.900.2.0

armadillo image Armadillo is a powerful and expressive C++ template library for linear algebra aiming towards a good balance between speed and ease of use with a syntax deliberately close to a Matlab. RcppArmadillo integrates this library with the R environment and language and is widely used by (currently) 757 other packages on CRAN. Conrad just released a new minor upstream version 9.900.2 of Armadillo which we packaged and tested as usual first as a release candidate build and then as the release. As usual, logs from reverse-depends runs are in the rcpp-logs repo. All changes in the new release are noted below.

Changes in RcppArmadillo version 0.9.900.2.0 (2020-07-17)
  • Upgraded to Armadillo release 9.900.2 (Nocturnal Misbehaviour)
    • In sort(), fixes for inconsistencies between checks applied to matrix and vector expressions
    • In sort(), remove unnecessary copying when applied in-place to vectors function when applied in-place to vectors

Courtesy of CRANberries, there is a diffstat report relative to previous release. More detailed information is on the RcppArmadillo page. Questions, comments etc should go to the rcpp-devel mailing list off the R-Forge page. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

16 July 2020

Louis-Philippe V ronneau: DebConf Videoteam Sprint Report -- DebConf20@Home

DebConf20 starts in about 5 weeks, and as always, the DebConf Videoteam is working hard to make sure it'll be a success. As such, we held a sprint from July 9th to 13th to work on our new infrastructure. A remote sprint certainly ain't as fun as an in-person one, but we nonetheless managed to enjoy ourselves. Many thanks to those who participated, namely: We also wish to extend our thanks to Thomas Goirand and Infomaniak for providing us with virtual machines to experiment on and host the video infrastructure for DebConf20. Advice for presenters For DebConf20, we strongly encourage presenters to record their talks in advance and send us the resulting video. We understand this is more work, but we think it'll make for a more agreeable conference for everyone. Video conferencing is still pretty wonky and there is nothing worse than a talk ruined by a flaky internet connection or hardware failures. As such, if you are giving a talk at DebConf this year, we are asking you to read and follow our guide on how to record your presentation. Fear not: we are not getting rid of the Q&A period at the end of talks. Attendees will ask their questions either on IRC or on a collaborative pad and the Talkmeister will relay them to the speaker once the pre-recorded video has finished playing. New infrastructure, who dis? Organising a virtual DebConf implies migrating from our battle-tested on-premise workflow to a completely new remote one. One of the major changes this means for us is the addition of Jitsi Meet to our infrastructure. We normally have 3 different video sources in a room: two cameras and a slides grabber. With the new online workflow, directors will be able to play pre-recorded videos as a source, will get a feed from a Jitsi room and will see the audience questions as a third source. This might seem simple at first, but is in fact a very major change to our workflow and required a lot of work to implement. 
               == On-premise ==                                          == Online ==
                                                      
              Camera 1                                                 Jitsi
                                                                          
                 v                 ---> Frontend                         v                 ---> Frontend
                                                                                            
    Slides -> Voctomix -> Backend -+--> Frontend         Questions -> Voctomix -> Backend -+--> Frontend
                                                                                            
                 ^                 ---> Frontend                         ^                 ---> Frontend
                                                                          
              Camera 2                                           Pre-recorded video
In our tests, playing back pre-recorded videos to voctomix worked well, but was sometimes unreliable due to inconsistent encoding settings. Presenters will thus upload their pre-recorded talks to SReview so we can make sure there aren't any obvious errors. Videos will then be re-encoded to ensure a consistent encoding and to normalise audio levels. This process will also let us stitch the Q&As at the end of the pre-recorded videos more easily prior to publication. Reducing the stream latency One of the pitfalls of the streaming infrastructure we have been using since 2016 is high video latency. In a worst case scenario, remote attendees could get up to 45 seconds of latency, making participation in events like BoFs arduous. In preparation for DebConf20, we added a new way to stream our talks: RTMP. Attendees will thus have the option of using either an HLS stream with higher latency or an RTMP stream with lower latency. Here is a comparative table that can help you decide between the two protocols:
HLS RTMP
Pros
  • Can be watched from a browser
  • Auto-selects a stream encoding
  • Single URL to remember
  • Lower latency (~5s)
Cons
  • Higher latency (up to 45s)
  • Requires a dedicated video player (VLC, mpv)
  • Specific URLs for each encoding setting
Live mixing from home with VoctoWeb Since DebConf16, we have been using voctomix, a live video mixer developed by the CCC VOC. voctomix is conveniently divided in two: voctocore is the backend server while voctogui is a GTK+ UI frontend directors can use to live-mix. Although voctogui can connect to a remote server, it was primarily designed to run either on the same machine as voctocore or on the same LAN. Trying to use voctogui from a machine at home to connect to a voctocore running in a datacenter proved unreliable, especially for high-latency and low bandwidth connections. Inspired by the setup FOSDEM uses, we instead decided to go with a web frontend for voctocore. We initially used FOSDEM's code as a proof of concept, but quickly reimplemented it in Python, a language we are more familiar with as a team. Compared to the FOSDEM PHP implementation, voctoweb implements A / B source selection (akin to voctogui) as well as audio control, two very useful features. In the following screen captures, you can see the old PHP UI on the left and the new shiny Python one on the right. The old PHP voctowebThe new Python3 voctoweb Voctoweb is still under development and is likely to change quite a bit until DebConf20. Still, the current version seems to works well enough to be used in production if you ever need to. Python GeoIP redirector We run multiple geographically-distributed streaming frontend servers to minimize the load on our streaming backend and to reduce overall latency. Although users can connect to the frontends directly, we typically point them to live.debconf.org and redirect connections to the nearest server. Sadly, 6 months ago MaxMind decided to change the licence on their GeoLite2 database and left us scrambling. To fix this annoying issue, Stefano Rivera wrote a Python program that uses the new database and reworked our ansible frontend server role. Since the new database cannot be redistributed freely, you'll have to get a (free) license key from MaxMind if you to use this role. Ansible & CI improvements Infrastructure as code is a living process and needs constant care to fix bugs, follow changes in DSL and to implement new features. All that to say a large part of the sprint was spent making our ansible roles and continuous integration setup more reliable, less buggy and more featureful. All in all, we merged 26 separate ansible-related merge request during the sprint! As always, if you are good with ansible and wish to help, we accept merge requests on our ansible repository :)

Enrico Zini: Build Qt5 cross-builder with raspbian sysroot: compiling with the sysroot

Whack-A-Mole machines from <https://commons.wikimedia.org/wiki/File:Whac-A-Mole_Cedar_Point.jpg> This is part of a series of posts on compiling a custom version of Qt5 in order to develop for both amd64 and a Raspberry Pi. Now that I have a sysroot, I try to use it to build Qt5 with QtWebEngine. Nothing seems to work straightforwardly with Qt5's build system, and hit an endless series of significant blockers to try and work around.
Problem in wayland code QtWayland's source currently does not compile: 
../../../hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.cpp: In constructor  QtWaylandClient::QWaylandBrcmEglWindow::QWaylandBrcmEglWindow(QWindow*) :
../../../hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.cpp:131:67: error: no matching function for call to  QtWaylandClient::QWaylandWindow::QWaylandWindow(QWindow*&) 
     , m_eventQueue(wl_display_create_queue(mDisplay->wl_display()))
                                                                   ^
In file included from ../../../../include/QtWaylandClient/5.15.0/QtWaylandClient/private/qwaylandwindow_p.h:1,
                 from ../../../hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.h:43,
                 from ../../../hardwareintegration/client/brcm-egl/qwaylandbrcmeglwindow.cpp:40:
../../../../include/QtWaylandClient/5.15.0/QtWaylandClient/private/../../../../../src/client/qwaylandwindow_p.h:97:5: note: candidate:  QtWaylandClient::QWaylandWindow::QWaylandWindow(QWindow*, QtWayland
Client::QWaylandDisplay*) 
     QWaylandWindow(QWindow *window, QWaylandDisplay *display);
     ^~~~~~~~~~~~~~
../../../../include/QtWaylandClient/5.15.0/QtWaylandClient/private/../../../../../src/client/qwaylandwindow_p.h:97:5: note:   candidate expects 2 arguments, 1 provided
make[5]: Leaving directory '/home/build/armhf/qt-everywhere-src-5.15.0/qttools/src/qdoc'
I am not trying to debug here. I understand that Wayland support is not a requirement, and I'm adding -skip wayland to Qt5's configure options. Next round. nss not found Qt5 embeds Chrome's sources. Chrome's sources require libnss3-dev to be available for both host and target architectures. Although I now have it installed both on the build system and in the sysroot, the pkg-config wrapper that Qt5 hooks into its Chrome's sources, failes to find it: 
Command: /usr/bin/python2 /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/3rdparty/chromium/build/config/linux/pkg-config.py -s /home/build/sysroot/ -a arm -p /usr/bin/arm-linux-gnueabihf-pkg-config --system_libdir lib nss -v -lssl3
Returned 1.
stderr:
Package nss was not found in the pkg-config search path.
Perhaps you should add the directory containing  nss.pc'
to the PKG_CONFIG_PATH environment variable
No package 'nss' found
Traceback (most recent call last):
  File "/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/3rdparty/chromium/build/config/linux/pkg-config.py", line 248, in <module>
    sys.exit(main())
  File "/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/3rdparty/chromium/build/config/linux/pkg-config.py", line 143, in main
    prefix = GetPkgConfigPrefixToStrip(options, args)
  File "/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/3rdparty/chromium/build/config/linux/pkg-config.py", line 82, in GetPkgConfigPrefixToStrip
    "--variable=prefix"] + args, env=os.environ).decode('utf-8')
  File "/usr/lib/python2.7/subprocess.py", line 223, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '['/usr/bin/arm-linux-gnueabihf-pkg-config', '--variable=prefix', 'nss']' returned non-zero exit status 1
See //build/config/linux/nss/BUILD.gn:15:3: whence it was called.
  pkg_config("system_nss_no_ssl_config")  
  ^---------------------------------------
See //crypto/BUILD.gn:218:25: which caused the file to be included.
    public_configs += [ "//build/config/linux/nss:system_nss_no_ssl_config" ]
                        ^--------------------------------------------------
Project ERROR: GN run error!
It's trying to look into $SYSROOT/usr/lib/pkgconfig, while it should be $SYSROOT//usr/lib/arm-linux-gnueabihf/pkgconfig. I worked around this this patch to qtwebengine/src/3rdparty/chromium/build/config/linux/pkg-config.py: 
--- pkg-config.py.orig  2020-07-16 11:46:21.005373002 +0200
+++ pkg-config.py   2020-07-16 11:46:02.605296967 +0200
@@ -61,6 +61,7 @@
   libdir = sysroot + '/usr/' + options.system_libdir + '/pkgconfig'
   libdir += ':' + sysroot + '/usr/share/pkgconfig'
+  libdir += ':' + sysroot + '/usr/lib/arm-linux-gnueabihf/pkgconfig'
   os.environ['PKG_CONFIG_LIBDIR'] = libdir
   return libdir
Next round. g++ 8.3.0 Internal Compiler Error Qt5's sources embed Chrome's sources that embed the skia library sources. One of the skia library sources, when cross-compiled to ARM with -O1 or -O2 with g++ 8.3.0, produces an Internal Compiler Error: 
/usr/bin/arm-linux-gnueabihf-g++ -MMD -MF obj/skia/skcms/skcms.o.d -DUSE_UDEV -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DOFFICIAL_BUILD -DTOOLKIT_QT -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DNO_UNWIND_TABLES -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DCR_SYSROOT_HASH=76e6068f9f6954e2ab1ff98ce5fa236d3d85bcbd -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -I../../3rdparty/chromium/third_party/skia/include/third_party/skcms -Igen -I../../3rdparty/chromium -w -std=c11 -mfp16-format=ieee -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -fno-unwind-tables -fno-asynchronous-unwind-tables -fPIC -pipe -pthread -march=armv7-a -mfloat-abi=hard -mtune=generic-armv7-a -mfpu=vfpv3-d16 -mthumb -Wall -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wno-psabi -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-deprecated-declarations -fno-delete-null-pointer-checks -Wno-comments -Wno-packed-not-aligned -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-parameter -O2 -fno-ident -fdata-sections -ffunction-sections -fno-omit-frame-pointer -g0 -fvisibility=hidden -std=gnu++14 -Wno-narrowing -Wno-class-memaccess -Wno-attributes -Wno-class-memaccess -Wno-subobject-linkage -Wno-invalid-offsetof -Wno-return-type -Wno-deprecated-copy -fno-exceptions -fno-rtti --sysroot=../../../../../../sysroot/ -fvisibility-inlines-hidden -c ../../3rdparty/chromium/third_party/skia/third_party/skcms/skcms.cc -o obj/skia/skcms/skcms.o
during RTL pass: expand
In file included from ../../3rdparty/chromium/third_party/skia/third_party/skcms/skcms.cc:2053:
../../3rdparty/chromium/third_party/skia/third_party/skcms/src/Transform_inl.h: In function  void baseline::exec_ops(const Op*, const void**, const char*, char*, int) :
../../3rdparty/chromium/third_party/skia/third_party/skcms/src/Transform_inl.h:766:13: internal compiler error: in convert_move, at expr.c:218
 static void exec_ops(const Op* ops, const void** args,
             ^~~~~~~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-8/README.Bugs> for instructions.
I reported the bug at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96206 Since this source compiles with -O0, I attempted to fix this by editing qtwebkit/src/3rdparty/chromium/build/config/compiler/BUILD.gn and replacing instances of -O1 and -O2 with -O0. Spoiler: wrong attempt. We'll see it in the next round. Impossible constraint in asm Qt5's sources embed Chrome's sources that embed the ffmpeg library sources. Even if ffmpeg's development libraries are present both in the host and in the target system, the build system insists in compiling and using the bundled version. Unfortunately, using -O0 breaks the build of ffmpeg: 
/usr/bin/arm-linux-gnueabihf-gcc -MMD -MF obj/third_party/ffmpeg/ffmpeg_internal/opus.o.d -DHAVE_AV_CONFIG_H -D_POSIX_C_SOURCE=200112 -D_XOPEN_SOURCE=600 -DPIC -DFFMPEG_CONFIGURATION=NULL -DCHROMIUM_NO_LOGGING -D_ISOC99_SOURCE -D_LARGEFILE_SOURCE -DUSE_UDEV -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DOFFICIAL_BUILD -DTOOLKIT_QT -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DNO_UNWIND_TABLES -DCR_SYSROOT_HASH=76e6068f9f6954e2ab1ff98ce5fa236d3d85bcbd -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DOPUS_FIXED_POINT -I../../3rdparty/chromium/third_party/ffmpeg/chromium/config/Chromium/linux/arm -I../../3rdparty/chromium/third_party/ffmpeg -I../../3rdparty/chromium/third_party/ffmpeg/compat/atomics/gcc -Igen -I../../3rdparty/chromium -I../../3rdparty/chromium/third_party/opus/src/include -fPIC -Wno-deprecated-declarations -fomit-frame-pointer -w -std=c99 -pthread -fno-math-errno -fno-signed-zeros -fno-tree-vectorize -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -fno-unwind-tables -fno-asynchronous-unwind-tables -fPIC -pipe -pthread -march=armv7-a -mfloat-abi=hard -mtune=generic-armv7-a -mfpu=vfpv3-d16 -mthumb -g0 -fvisibility=hidden -Wno-psabi -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-deprecated-declarations -fno-delete-null-pointer-checks -Wno-comments -Wno-packed-not-aligned -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-parameter -O0 -fno-ident -fdata-sections -ffunction-sections -std=gnu11 --sysroot=../../../../../../sysroot/ -c ../../3rdparty/chromium/third_party/ffmpeg/libavcodec/opus.c -o obj/third_party/ffmpeg/ffmpeg_internal/opus.o
In file included from ../../3rdparty/chromium/third_party/ffmpeg/libavutil/intmath.h:30,
                 from ../../3rdparty/chromium/third_party/ffmpeg/libavutil/common.h:106,
                 from ../../3rdparty/chromium/third_party/ffmpeg/libavutil/avutil.h:296,
                 from ../../3rdparty/chromium/third_party/ffmpeg/libavutil/audio_fifo.h:30,
                 from ../../3rdparty/chromium/third_party/ffmpeg/libavcodec/opus.h:28,
                 from ../../3rdparty/chromium/third_party/ffmpeg/libavcodec/opus_celt.h:29,
                 from ../../3rdparty/chromium/third_party/ffmpeg/libavcodec/opus.c:32:
../../3rdparty/chromium/third_party/ffmpeg/libavcodec/opus.c: In function  ff_celt_quant_bands :
../../3rdparty/chromium/third_party/ffmpeg/libavutil/arm/intmath.h:77:5: error: impossible constraint in  asm 
     __asm__ ("usat %0, %2, %1" : "=r"(x) : "r"(a), "i"(p));
     ^~~~~~~
The same source compiles with using -O2 instead of -O0. I worked around this by undoing the previous change, and limiting -O0 to just the source that causes the Internal Compiler Error. I edited qtwebengine/src/3rdparty/chromium/third_party/skia/third_party/skcms/skcms.cc to prepend: 
#pragma GCC push_options
#pragma GCC optimize ("O0")
and append: 
#pragma GCC pop_options
Next round. Missing build-deps for i386 code Qt5's sources embed Chrome's sources that embed the V8 library sources. For some reason, torque, that is part of V8, wants to build some of its sources into 32 bit code with -m32, and I did not have i386 cross-compilation libraries installed: 
/usr/bin/g++ -MMD -MF v8_snapshot/obj/v8/torque_base/csa-generator.o.d -DUSE_UDEV -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DOFFICIAL_BUILD -DTOOLKIT_QT -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DNO_UNWIND_TABLES -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DV8_TYPED_ARRAY_MAX_SIZE_IN_HEAP=64 -DENABLE_MINOR_MC -DV8_INTL_SUPPORT -DV8_CONCURRENT_MARKING -DV8_ENABLE_LAZY_SOURCE_POSITIONS -DV8_EMBEDDED_BUILTINS -DV8_SHARED_RO_HEAP -DV8_WIN64_UNWINDING_INFO -DV8_ENABLE_REGEXP_INTERPRETER_THREADED_DISPATCH -DV8_31BIT_SMIS_ON_64BIT_ARCH -DV8_DEPRECATION_WARNINGS -DV8_TARGET_ARCH_ARM -DCAN_USE_ARMV7_INSTRUCTIONS -DCAN_USE_VFP3_INSTRUCTIONS -DUSE_EABI_HARDFLOAT=1 -DV8_HAVE_TARGET_OS -DV8_TARGET_OS_LINUX -DDISABLE_UNTRUSTED_CODE_MITIGATIONS -DV8_31BIT_SMIS_ON_64BIT_ARCH -DV8_DEPRECATION_WARNINGS -Iv8_snapshot/gen -I../../3rdparty/chromium -I../../3rdparty/chromium/v8 -Iv8_snapshot/gen/v8 -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -fno-unwind-tables -fno-asynchronous-unwind-tables -fPIC -pipe -pthread -m32 -msse2 -mfpmath=sse -mmmx -Wall -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-deprecated-declarations -fno-delete-null-pointer-checks -Wno-comments -Wno-packed-not-aligned -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-parameter -fno-omit-frame-pointer -g0 -fvisibility=hidden -Wno-strict-overflow -Wno-return-type -O3 -fno-ident -fdata-sections -ffunction-sections -std=gnu++14 -Wno-narrowing -Wno-class-memaccess -Wno-attributes -Wno-class-memaccess -Wno-subobject-linkage -Wno-invalid-offsetof -Wno-return-type -Wno-deprecated-copy -fvisibility-inlines-hidden -fexceptions -frtti -c ../../3rdparty/chromium/v8/src/torque/csa-generator.cc -o v8_snapshot/obj/v8/torque_base/csa-generator.o
In file included from ../../3rdparty/chromium/v8/src/torque/csa-generator.h:8,
                 from ../../3rdparty/chromium/v8/src/torque/csa-generator.cc:5:
/usr/include/c++/8/iostream:38:10: fatal error: bits/c++config.h: No such file or directory
 #include <bits/c++config.h>
          ^~~~~~~~~~~~~~~~~~
compilation terminated.
New build dependencies needed: 
apt install lib32stdc++-8-dev
apt install libc6-dev-i386
dpkg --add-architecture i386
apt install linux-libc-dev:i386
Next round. OpenGL build issues Next bump are OpenGL related compiler issues: 
/usr/bin/arm-linux-gnueabihf-g++ -MMD -MF obj/QtWebEngineCore/gl_ozone_glx_qt.o.d -DCHROMIUM_VERSION=\"80.0.3987.163\" -DUSE_UDEV -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DOFFICIAL_BUILD -DTOOLKIT_QT -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DNO_UNWIND_TABLES -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DCR_SYSROOT_HASH=76e6068f9f6954e2ab1ff98ce5fa236d3d85bcbd -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DQT_NO_LINKED_LIST -DQT_NO_KEYWORDS -DQT_USE_QSTRINGBUILDER -DQ_FORWARD_DECLARE_OBJC_CLASS=QT_FORWARD_DECLARE_CLASS -DQTWEBENGINECORE_VERSION_STR=\"5.15.0\" -DQTWEBENGINEPROCESS_NAME=\"QtWebEngineProcess\" -DBUILDING_CHROMIUM -DQTWEBENGINE_EMBEDDED_SWITCHES -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QMLMODELS_LIB -DQT_WEBCHANNEL_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_POSITIONING_LIB -DQT_CORE_LIB -DQT_WEBENGINECOREHEADERS_LIB -DVK_NO_PROTOTYPES -DGL_GLEXT_PROTOTYPES -DUSE_GLX -DUSE_EGL -DGOOGLE_PROTOBUF_NO_RTTI -DGOOGLE_PROTOBUF_NO_STATIC_INITIALIZER -DHAVE_PTHREAD -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DUSE_CHROMIUM_ICU=1 -DU_STATIC_IMPLEMENTATION -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE -DUCHAR_TYPE=uint16_t -DWEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS=0 -DWEBRTC_CHROMIUM_BUILD -DWEBRTC_POSIX -DWEBRTC_LINUX -DABSL_ALLOCATOR_NOTHROW=1 -DWEBRTC_USE_BUILTIN_ISAC_FIX=1 -DWEBRTC_USE_BUILTIN_ISAC_FLOAT=0 -DHAVE_SCTP -DNO_MAIN_THREAD_WRAPPING -DSK_HAS_PNG_LIBRARY -DSK_HAS_WEBP_LIBRARY -DSK_USER_CONFIG_HEADER=\"../../skia/config/SkUserConfig.h\" -DSK_GL -DSK_HAS_JPEG_LIBRARY -DSK_USE_LIBGIFCODEC -DSK_VULKAN_HEADER=\"../../skia/config/SkVulkanConfig.h\" -DSK_VULKAN=1 -DSK_SUPPORT_GPU=1 -DSK_GPU_WORKAROUNDS_HEADER=\"gpu/config/gpu_driver_bug_workaround_autogen.h\" -DVK_NO_PROTOTYPES -DLEVELDB_PLATFORM_CHROMIUM=1 -DLEVELDB_PLATFORM_CHROMIUM=1 -DV8_31BIT_SMIS_ON_64BIT_ARCH -DV8_DEPRECATION_WARNINGS -I../../3rdparty/chromium/skia/config -I../../3rdparty/chromium/third_party -I../../3rdparty/chromium/third_party/boringssl/src/include -I../../3rdparty/chromium/third_party/skia/include/core -Igen -I../../3rdparty/chromium -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/api -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQuick/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQuick/5.15.0/QtQuick -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtGui/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtGui/5.15.0/QtGui -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQuick -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtGui -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQmlModels/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQmlModels/5.15.0/QtQmlModels -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQml/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQml/5.15.0/QtQml -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtCore/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtCore/5.15.0/QtCore -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQmlModels -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebchannel/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebchannel/include/QtWebChannel -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQml -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtNetwork -I/home/build/armhf/qt-everywhere-src-5.15.0/qtlocation/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtlocation/include/QtPositioning -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtCore -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/include/QtWebEngineCore -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/include/QtWebEngineCore/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/include/QtWebEngineCore/5.15.0/QtWebEngineCore -I.moc -I/home/build/sysroot/opt/vc/include -I/home/build/sysroot/opt/vc/include/interface/vcos/pthreads -I/home/build/sysroot/opt/vc/include/interface/vmcs_host/linux -Igen/.moc -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/mkspecs/devices/linux-rasp-pi2-g++ -Igen -Igen -I../../3rdparty/chromium/third_party/libyuv/include -Igen -I../../3rdparty/chromium/third_party/jsoncpp/source/include -I../../3rdparty/chromium/third_party/jsoncpp/generated -Igen -Igen -I../../3rdparty/chromium/third_party/khronos -I../../3rdparty/chromium/gpu -I../../3rdparty/chromium/third_party/vulkan/include -I../../3rdparty/chromium/third_party/perfetto/include -Igen/third_party/perfetto/build_config -Igen -Igen -Igen/third_party/dawn/src/include -I../../3rdparty/chromium/third_party/dawn/src/include -Igen -I../../3rdparty/chromium/third_party/boringssl/src/include -I../../3rdparty/chromium/third_party/protobuf/src -Igen/protoc_out -I../../3rdparty/chromium/third_party/protobuf/src -I../../3rdparty/chromium/third_party/ced/src -I../../3rdparty/chromium/third_party/icu/source/common -I../../3rdparty/chromium/third_party/icu/source/i18n -I../../3rdparty/chromium/third_party/webrtc_overrides -I../../3rdparty/chromium/third_party/webrtc -Igen/third_party/webrtc -I../../3rdparty/chromium/third_party/abseil-cpp -I../../3rdparty/chromium/third_party/skia -I../../3rdparty/chromium/third_party/libgifcodec -I../../3rdparty/chromium/third_party/vulkan/include -I../../3rdparty/chromium/third_party/skia/third_party/vulkanmemoryallocator -I../../3rdparty/chromium/third_party/vulkan/include -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -I../../3rdparty/chromium/third_party/crashpad/crashpad -I../../3rdparty/chromium/third_party/crashpad/crashpad/compat/non_mac -I../../3rdparty/chromium/third_party/crashpad/crashpad/compat/linux -I../../3rdparty/chromium/third_party/crashpad/crashpad/compat/non_win -I../../3rdparty/chromium/third_party/libwebm/source -I../../3rdparty/chromium/third_party/leveldatabase -I../../3rdparty/chromium/third_party/leveldatabase/src -I../../3rdparty/chromium/third_party/leveldatabase/src/include -I../../3rdparty/chromium/v8/include -Igen/v8/include -I../../3rdparty/chromium/third_party/mesa_headers -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -fno-unwind-tables -fno-asynchronous-unwind-tables -fPIC -pipe -pthread -march=armv7-a -mfloat-abi=hard -mtune=generic-armv7-a -mfpu=vfpv3-d16 -mthumb -Wall -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wno-psabi -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-deprecated-declarations -fno-delete-null-pointer-checks -Wno-comments -Wno-packed-not-aligned -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-parameter -O2 -fno-ident -fdata-sections -ffunction-sections -fno-omit-frame-pointer -g0 -fvisibility=hidden -g -O2 -fdebug-prefix-map=/home/build/armhf/qt-everywhere-src-5.15.0=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O2 -fno-exceptions -Wall -Wextra -D_REENTRANT -I/home/build/sysroot/usr/include/nss -I/home/build/sysroot/usr/include/nspr -std=gnu++14 -Wno-narrowing -Wno-class-memaccess -Wno-attributes -Wno-class-memaccess -Wno-subobject-linkage -Wno-invalid-offsetof -Wno-return-type -Wno-deprecated-copy -fno-exceptions -fno-rtti --sysroot=../../../../../../sysroot/ -fvisibility-inlines-hidden -g -O2 -fdebug-prefix-map=/home/build/armhf/qt-everywhere-src-5.15.0=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O2 -std=gnu++1y -fno-exceptions -Wall -Wextra -D_REENTRANT -Wno-unused-parameter -Wno-unused-variable -Wno-deprecated-declarations -c /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/ozone/gl_ozone_glx_qt.cpp -o obj/QtWebEngineCore/gl_ozone_glx_qt.o
In file included from ../../3rdparty/chromium/ui/gl/gl_bindings.h:497,
                 from ../../3rdparty/chromium/ui/gl/gl_gl_api_implementation.h:12,
                 from /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/ozone/gl_ozone_glx_qt.cpp:49:
../../3rdparty/chromium/ui/gl/gl_bindings_autogen_egl.h:227:5: error:  EGLSetBlobFuncANDROID  has not been declared
     EGLSetBlobFuncANDROID set,
     ^~~~~~~~~~~~~~~~~~~~~
../../3rdparty/chromium/ui/gl/gl_bindings_autogen_egl.h:228:5: error:  EGLGetBlobFuncANDROID  has not been declared
     EGLGetBlobFuncANDROID get);
     ^~~~~~~~~~~~~~~~~~~~~
../../3rdparty/chromium/ui/gl/gl_bindings_autogen_egl.h:571:46: error:  EGLSetBlobFuncANDROID  has not been declared
                                              EGLSetBlobFuncANDROID set,
                                              ^~~~~~~~~~~~~~~~~~~~~
../../3rdparty/chromium/ui/gl/gl_bindings_autogen_egl.h:572:46: error:  EGLGetBlobFuncANDROID  has not been declared
                                              EGLGetBlobFuncANDROID get) = 0;
                                              ^~~~~~~~~~~~~~~~~~~~~
cc1plus: warning: unrecognized command line option  -Wno-deprecated-copy 

/usr/bin/arm-linux-gnueabihf-g++ -MMD -MF obj/QtWebEngineCore/display_gl_output_surface.o.d -DCHROMIUM_VERSION=\"80.0.3987.163\" -DUSE_UDEV -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DOFFICIAL_BUILD -DTOOLKIT_QT -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DNO_UNWIND_TABLES -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DCR_SYSROOT_HASH=76e6068f9f6954e2ab1ff98ce5fa236d3d85bcbd -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DQT_NO_LINKED_LIST -DQT_NO_KEYWORDS -DQT_USE_QSTRINGBUILDER -DQ_FORWARD_DECLARE_OBJC_CLASS=QT_FORWARD_DECLARE_CLASS -DQTWEBENGINECORE_VERSION_STR=\"5.15.0\" -DQTWEBENGINEPROCESS_NAME=\"QtWebEngineProcess\" -DBUILDING_CHROMIUM -DQTWEBENGINE_EMBEDDED_SWITCHES -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_QMLMODELS_LIB -DQT_WEBCHANNEL_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_POSITIONING_LIB -DQT_CORE_LIB -DQT_WEBENGINECOREHEADERS_LIB -DVK_NO_PROTOTYPES -DGL_GLEXT_PROTOTYPES -DUSE_GLX -DUSE_EGL -DGOOGLE_PROTOBUF_NO_RTTI -DGOOGLE_PROTOBUF_NO_STATIC_INITIALIZER -DHAVE_PTHREAD -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DUSE_CHROMIUM_ICU=1 -DU_STATIC_IMPLEMENTATION -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE -DUCHAR_TYPE=uint16_t -DWEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS=0 -DWEBRTC_CHROMIUM_BUILD -DWEBRTC_POSIX -DWEBRTC_LINUX -DABSL_ALLOCATOR_NOTHROW=1 -DWEBRTC_USE_BUILTIN_ISAC_FIX=1 -DWEBRTC_USE_BUILTIN_ISAC_FLOAT=0 -DHAVE_SCTP -DNO_MAIN_THREAD_WRAPPING -DSK_HAS_PNG_LIBRARY -DSK_HAS_WEBP_LIBRARY -DSK_USER_CONFIG_HEADER=\"../../skia/config/SkUserConfig.h\" -DSK_GL -DSK_HAS_JPEG_LIBRARY -DSK_USE_LIBGIFCODEC -DSK_VULKAN_HEADER=\"../../skia/config/SkVulkanConfig.h\" -DSK_VULKAN=1 -DSK_SUPPORT_GPU=1 -DSK_GPU_WORKAROUNDS_HEADER=\"gpu/config/gpu_driver_bug_workaround_autogen.h\" -DVK_NO_PROTOTYPES -DLEVELDB_PLATFORM_CHROMIUM=1 -DLEVELDB_PLATFORM_CHROMIUM=1 -DV8_31BIT_SMIS_ON_64BIT_ARCH -DV8_DEPRECATION_WARNINGS -I../../3rdparty/chromium/skia/config -I../../3rdparty/chromium/third_party -I../../3rdparty/chromium/third_party/boringssl/src/include -I../../3rdparty/chromium/third_party/skia/include/core -Igen -I../../3rdparty/chromium -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/api -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQuick/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQuick/5.15.0/QtQuick -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtGui/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtGui/5.15.0/QtGui -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQuick -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtGui -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQmlModels/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQmlModels/5.15.0/QtQmlModels -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQml/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQml/5.15.0/QtQml -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtCore/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtCore/5.15.0/QtCore -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQmlModels -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebchannel/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebchannel/include/QtWebChannel -I/home/build/armhf/qt-everywhere-src-5.15.0/qtdeclarative/include/QtQml -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtNetwork -I/home/build/armhf/qt-everywhere-src-5.15.0/qtlocation/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtlocation/include/QtPositioning -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/include/QtCore -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/include -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/include/QtWebEngineCore -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/include/QtWebEngineCore/5.15.0 -I/home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/include/QtWebEngineCore/5.15.0/QtWebEngineCore -I.moc -I/home/build/sysroot/opt/vc/include -I/home/build/sysroot/opt/vc/include/interface/vcos/pthreads -I/home/build/sysroot/opt/vc/include/interface/vmcs_host/linux -Igen/.moc -I/home/build/armhf/qt-everywhere-src-5.15.0/qtbase/mkspecs/devices/linux-rasp-pi2-g++ -Igen -Igen -I../../3rdparty/chromium/third_party/libyuv/include -Igen -I../../3rdparty/chromium/third_party/jsoncpp/source/include -I../../3rdparty/chromium/third_party/jsoncpp/generated -Igen -Igen -I../../3rdparty/chromium/third_party/khronos -I../../3rdparty/chromium/gpu -I../../3rdparty/chromium/third_party/vulkan/include -I../../3rdparty/chromium/third_party/perfetto/include -Igen/third_party/perfetto/build_config -Igen -Igen -Igen/third_party/dawn/src/include -I../../3rdparty/chromium/third_party/dawn/src/include -Igen -I../../3rdparty/chromium/third_party/boringssl/src/include -I../../3rdparty/chromium/third_party/protobuf/src -Igen/protoc_out -I../../3rdparty/chromium/third_party/protobuf/src -I../../3rdparty/chromium/third_party/ced/src -I../../3rdparty/chromium/third_party/icu/source/common -I../../3rdparty/chromium/third_party/icu/source/i18n -I../../3rdparty/chromium/third_party/webrtc_overrides -I../../3rdparty/chromium/third_party/webrtc -Igen/third_party/webrtc -I../../3rdparty/chromium/third_party/abseil-cpp -I../../3rdparty/chromium/third_party/skia -I../../3rdparty/chromium/third_party/libgifcodec -I../../3rdparty/chromium/third_party/vulkan/include -I../../3rdparty/chromium/third_party/skia/third_party/vulkanmemoryallocator -I../../3rdparty/chromium/third_party/vulkan/include -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -Igen/third_party/perfetto -I../../3rdparty/chromium/third_party/crashpad/crashpad -I../../3rdparty/chromium/third_party/crashpad/crashpad/compat/non_mac -I../../3rdparty/chromium/third_party/crashpad/crashpad/compat/linux -I../../3rdparty/chromium/third_party/crashpad/crashpad/compat/non_win -I../../3rdparty/chromium/third_party/libwebm/source -I../../3rdparty/chromium/third_party/leveldatabase -I../../3rdparty/chromium/third_party/leveldatabase/src -I../../3rdparty/chromium/third_party/leveldatabase/src/include -I../../3rdparty/chromium/v8/include -Igen/v8/include -I../../3rdparty/chromium/third_party/mesa_headers -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -fno-unwind-tables -fno-asynchronous-unwind-tables -fPIC -pipe -pthread -march=armv7-a -mfloat-abi=hard -mtune=generic-armv7-a -mfpu=vfpv3-d16 -mthumb -Wall -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wno-psabi -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-deprecated-declarations -fno-delete-null-pointer-checks -Wno-comments -Wno-packed-not-aligned -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-parameter -O2 -fno-ident -fdata-sections -ffunction-sections -fno-omit-frame-pointer -g0 -fvisibility=hidden -g -O2 -fdebug-prefix-map=/home/build/armhf/qt-everywhere-src-5.15.0=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O2 -fno-exceptions -Wall -Wextra -D_REENTRANT -I/home/build/sysroot/usr/include/nss -I/home/build/sysroot/usr/include/nspr -std=gnu++14 -Wno-narrowing -Wno-class-memaccess -Wno-attributes -Wno-class-memaccess -Wno-subobject-linkage -Wno-invalid-offsetof -Wno-return-type -Wno-deprecated-copy -fno-exceptions -fno-rtti --sysroot=../../../../../../sysroot/ -fvisibility-inlines-hidden -g -O2 -fdebug-prefix-map=/home/build/armhf/qt-everywhere-src-5.15.0=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O2 -std=gnu++1y -fno-exceptions -Wall -Wextra -D_REENTRANT -Wno-unused-parameter -Wno-unused-variable -Wno-deprecated-declarations -c /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/compositor/display_gl_output_surface.cpp -o obj/QtWebEngineCore/display_gl_output_surface.o
In file included from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_interface.h:8,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/client_transfer_cache.h:15,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_implementation.h:28,
                 from /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/compositor/display_gl_output_surface.cpp:47:
/home/build/sysroot/opt/vc/include/GLES2/gl2.h:78: warning: "GL_FALSE" redefined
 #define GL_FALSE                          (GLboolean)0
In file included from ../../3rdparty/chromium/gpu/command_buffer/client/client_context_state.h:10,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_implementation.h:27,
                 from /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/compositor/display_gl_output_surface.cpp:47:
../../3rdparty/chromium/third_party/khronos/GLES3/gl3.h:85: note: this is the location of the previous definition
 #define GL_FALSE                          0
In file included from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_interface.h:8,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/client_transfer_cache.h:15,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_implementation.h:28,
                 from /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/compositor/display_gl_output_surface.cpp:47:
/home/build/sysroot/opt/vc/include/GLES2/gl2.h:79: warning: "GL_TRUE" redefined
 #define GL_TRUE                           (GLboolean)1
In file included from ../../3rdparty/chromium/gpu/command_buffer/client/client_context_state.h:10,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_implementation.h:27,
                 from /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/compositor/display_gl_output_surface.cpp:47:
../../3rdparty/chromium/third_party/khronos/GLES3/gl3.h:86: note: this is the location of the previous definition
 #define GL_TRUE                           1
In file included from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_interface.h:8,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/client_transfer_cache.h:15,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_implementation.h:28,
                 from /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/compositor/display_gl_output_surface.cpp:47:
/home/build/sysroot/opt/vc/include/GLES2/gl2.h:600:37: error: conflicting declaration of C function  void glShaderSource(GLuint, GLsizei, const GLchar**, const GLint*) 
 GL_APICALL void         GL_APIENTRY glShaderSource (GLuint shader, GLsizei count, const GLchar** string, const GLint* length);
                                     ^~~~~~~~~~~~~~
In file included from ../../3rdparty/chromium/gpu/command_buffer/client/client_context_state.h:10,
                 from ../../3rdparty/chromium/gpu/command_buffer/client/gles2_implementation.h:27,
                 from /home/build/armhf/qt-everywhere-src-5.15.0/qtwebengine/src/core/compositor/display_gl_output_surface.cpp:47:
../../3rdparty/chromium/third_party/khronos/GLES3/gl3.h:624:29: note: previous declaration  void glShaderSource(GLuint, GLsizei, const GLchar* const*, const GLint*) 
 GL_APICALL void GL_APIENTRY glShaderSource (GLuint shader, GLsizei count, const GLchar *const*string, const GLint *length);
                             ^~~~~~~~~~~~~~
cc1plus: warning: unrecognized command line option  -Wno-deprecated-copy
I'm out of the allocated hour budget, and I'll stop here for now. Building Qt5 has been providing some of the most nightmarish work time in my entire professional life. If my daily job became being required to deal with this kind of insanity, I would strongly invest in a change of career. Update Andreas Gruber wrote:
Long story short, a fast solution for the issue with EGLSetBlobFuncANDROID is to remove libraspberrypi-dev from your sysroot and do a full rebuild. There will be some changes to the configure results, so please review them - if they are relevant for you - before proceeding with your work.
And thanks to Andreas, the story can continue...

15 July 2020

Evgeni Golov: Scanning with a Brother MFC-L2720DW on Linux without any binary blobs

Back in 2015, I've got a Brother MFC-L2720DW for the casual "I need to print those two pages" and "I need to scan these receipts" at home (and home-office ;)). It's a rather cheap (I paid less than 200 in 2015) monochrome laser printer, scanner and fax with a (well, two, wired and wireless) network interface. In those five years I've never used the fax or WiFi functions, but printed a scanned a few pages. Brother offers Linux drivers, but those are binary blobs which I never really liked to run. The printer part works just fine with a "Generic PCL 6/PCL XL" driver in CUPS or even "driverless" via AirPrint on Linux. You can also feed it plain PostScript, but I found it rather slow compared to PCL. On recent Androids it works using the built in printer service or Mopria Printer Service for older ones - I used to joke "why would you need a printer on your phone?!", but found it quite useful after a few tries. However, for the scanner part I had to use Brother's brscan4 driver on Linux and their iPrint&Scan app on Android - Mopria Scan wouldn't support it. Until, last Friday, I've seen a NEW package being uploaded to Debian: sane-airscan. And yes, monitoring the Debian NEW queue via Twitter is totally legit! sane-airscan is an implementation of Apple's AirScan (eSCL) and Microsoft's WSD/WS-Scan protocols for SANE. I've never heard of those before - only about AirPrint, but thankfully this does not mean nobody has reverse-engineered them and created something that works beautifully on Linux. As of today there are no packages in the official Fedora repositories and the Debian ones are still in NEW, however the upstream documentation refers to an openSUSE OBS repository that works like a charm in the meantime (on Fedora 32). The only drawback I've seen so far: the scanner only works in "Color" mode and there is no way to scan in "Grayscale", making scanning a tad slower. This has been reported upstream and might or might not be fixable, as it seems the device does not announce any mode besides "Color". Interestingly, SANE has an eSCL backend on its own since 1.0.29, but it's disabled in Fedora in favor of sane-airscan even though the later isn't available in Fedora yet. However, it might not even need separate packaging, as SANE upstream is planning to integrate it into sane-backends directly.

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